Bactérias consumidoras de fosfato em uma bacia hidrográfica urbana no centro da Amazônia

Abstract

The most widespread concerns regarding contamination by human and animal waste are caused by pathogens related to water-borne diseases and excessive concentrations of nitrogen and phosphorus that cause the phenomenon of eutrophication. Thus, this study aimed to evaluate the interaction between E. coli bacteria and phosphate levels in an urban watershed in Manaus. Fourteen fortnightly collections were carried out between September 2021 and March 2022. Watersamples for E. coli analysis were collected close to the surface in 100 mL glassflasks, whilefor phosphate analysis, samples were collected in polyethylene bottles and stored until analysis by Colilert and spectrophotometry, respectively. The results showed that the naturally acidic waters of Manaus had basic pH values in many places (up to 7.20) and that there is a linear trendbetween phosphate and E. coli. This microorganism prevailed in less acidic environments. At pHvalues close to 7.0, the phosphate concentration practically does not change, as if this ion wereassociated with some buffer in the medium (from 0.04 mg L-1 ). The E. coli predominated at all points whose phosphate concentrations were above 0.04 mg L-1 , following a typical logarithmic trend for microbial growth. Contrary to what was expected, there was no dilution towards the mouths of this hydrographic basin, neither for phosphate nor for E. coli.